Structural inequality really needs to be at the core of any notion of economic efficiency. The notion of "by the 1% for the 1%" applies to the market as much as it does to government: if a small, relatively homogeneous, group of people have control of excess amounts of capital due to structural inequality, then that market is not free. The interests of that wealthy minority will be given undue priority relative to the economic interests of the community at large.
Relying on the enlightened foresight of the elite to look after the interests of the community as a whole is foolish, because history has shown time and time again that it doesn't work. The elite almost inevitably attempt to secure their personal power at the expense of the community, and the system ultimately collapses in chaos (at least for a while).